The invention relates to the field of pharmaceutical compositions. In particular, the invention pertains to pharmaceutical formulations containing antihistamines, such as, loratadine and its derivatives that are formulated for use in conjunction with soft gelatin capsules.
Two identified histamine receptors are the receptors H-1 and H-2. The H-1 receptors mediate the response antagonized by conventional antihistamines. H-1 receptors are present in the mammalian skin, ileum and bronchial smooth muscle.
Non-narcotic or non-sedating hydrophobic antihistamine compounds such as loratadine and its derivatives are known. Loratadine was first described in U.S. Pat. No. 4,282,233 to Vilani. Loratadine is an H-1 histamine receptor protein antagonist which binds to peripheral H-1 receptors as discussed in Quercia et al., Hosp. Formul., 28, p.137-53 (1993). Loratadine is useful as an antihistamine and has little or no sedative effects. Thus, loratadine provides an antihistamine effect while still allowing the user to perform mental or physical functions requiring high levels of concentration. A variety of other therapeutic treatments using loratadine alone or in combination with other active ingredients have been suggested, such as treatment of seasonal or perennial rhinitis, allergic asthma, and motion sickness. See Aberg et al., U.S. Pat. No. 5,731,319, for example. Antiarrhythmic uses, such as treatment of atrial fibrillation (AF), have also been suggested, as described in Buckland et al., U.S. Pat. No. 6,110,927.
Loratadine derivatives which share antihistamine properties of loratadine have also been developed. Active metabolites such as decarbalkoxylated forms of loratadine have been of interest. One such metabolite derivative is 8-chloro-6,11-dihydro-11-(4-piperidylidine)-5H-benzo-[5,6]-cyclohepta-[1,2-b] pyridine, also known as descarboethoxyloratadine (DCL) which is described in U.S. Pat. No. 4,659,716. U.S. Pat. No. 5,595,997 to Aberg et al discloses methods of utilizing DCL for the treatment of allergic rhinitis and other disorders without adverse side effects.
Other patents relating to loratadine or a chemically related antihistamine, including any pharmaceutically acceptable salt thereof, in various dosage forms include U.S. Pat. No. 5,100,675 to Cho et al.; U.S. Pat. No. 4,990,535 to Cho et al.; and U.S. Pat. No. 5,314,697 to Kwan et al.
Oral dosage forms, such as loratadine-containing tablets and syrups, are known and marketed under the names Claritin(copyright), Claratin Reditabs(copyright) and Claratin-D(copyright) 24-Hour etc. (commercially available from Schering-Plough Corporation, N.J.).
These commercial products are described in U.S. Pat. No. 4,282,233 to Villani; U.S. Pat. No. 4,659,716 to Villani; U.S. Pat. No. 4,863,931 to Schumacher et al.; U.S. Pat. No. 6,132,758 to Munayyer et al. U.S. Pat. No. 6,132,758 discloses an antihistaminic syrup stabilized against degradation of the active ingredient by the addition of about 0.05 to 5 mg/mL of an amino-polycorboxylic acid. This patent teaches that under certain storage conditions losses of active agent can occur.
U.S. Pat. No. 4,910,205 to Kogan et al discloses a transdermally acceptable composition comprising an effective amount of loratadine or its decarbalhoxylation product, about 40-70% weight % of a volatile solvent, about 5-50% by weight of a fatty acid ester and about 2-60% of an essential oil.
While syrup, solid and fast dissolving dosage forms are available for loratadine type antihistamines, there presently exists a need for a soft capsule dosage form. The soft capsule dosage form has many advantages known to those skilled in the art, however, formulating hydrophobic drugs into solutions for encapsulation into a soft capsule can present many problems. Oral delivery systems for hydrophobic drugs are known. Lacy et al. U.S. Pat. No. 6,096,338 describes delivery systems for hydrophobic drugs including histamine H-1 receptor antagonists such as loratadine. The carrier systems disclosed include a digestible oil, preferably mixtures of partial or complete esters of medium chain fatty acids, and a pharmaceutically acceptable surfactant component comprising a hydrophilic surfactant containing a transesterification product of polyoxyethylene glycol with glycerol esters of capric and/or caprylic acids. This surfactant disperses the oil in vivo without substantially inhibiting in vivo lipolysis of the oil. The reference does not, however, specifically address the problems associated with storage stability and recrystallization of loratadine and its derivatives in soft capsule dosage forms.
Hydrophobic solvents are preferred for use in soft capsules so as to reduce the hydrophilic nature of the fill, wherein migration of water through the soft capsular material into the fill composition can cause recrystallization and precipitation of the active ingredient under storage conditions. One problem associated with hydrophobic solvents, however, is that they are known to adversely affect bioavailability of the drug. Compounds such as loratadine are susceptible to recrystallization and therefore experience the solvent system challenges associated with soft capsules. Ideally, a solvent system for loratadine and its derivatives is one which is hydrophobic, protonic and water-dispersible.
There thus exists a need for improved pharmaceutical formulations containing loratadine and derivatives thereof for use in soft capsules which solubilize loratadine and exhibit long-term storage stability at ambient conditions without recrystallization. There is also a need for a solvent system which does not adversely affect bioavailability of the active ingredient. Even more desirable would be a formulation which satisfies both of these criteria and also increase the fill concentration of loratadine. This would permit the use of smaller size capsules for a given dose of active.
The invention provides for a pharmaceutical composition comprising loratadine and its derivatives together with a solvent system for use in soft capsules. Loratadine compositions of the invention exhibit unexpected and improved solubilization properties at ambient storage conditions over extended period of time without recrystallization and precipitation of loratadine. The inventive composition also permits higher concentrations of loratadine to be delivered within a given fill volume. As a result, the total amount of fill volume needed to administer the same dosage of loratadine is reduced, and smaller capsule sizes can be used thereby improving patient comfort and reducing manufacturing costs.
The invention provides a pharmaceutical composition for use in soft capsules comprising loratadine and derivatives thereof and a solvent system comprising a mixture of mono- and diglycerides of medium chain fatty acids. In a more preferred embodiment the invention provides a pharmaceutical composition that additionally comprises a dispersant. In a most preferred embodiment the dispersant comprises povidone and Polysorbate(trademark) 80.
There is further disclosed a pharmaceutical composition for use in soft capsule dosage form consisting essentially of:
a) loratadine and derivatives thereof present in an amount of about 6.3% by weight of the total composition;
b) mono- and di-glycerides of medium chain fatty acids present in an amount of about 87% by weight of the total composition;
c) povidone present in an amount of about 6.3% by weight of the total composition; and
d) Polysorbate(trademark) 80 present in an amount of about 0.8% by weight of the total composition.
There is also disclosed a pharmaceutical composition for use in soft capsule dosage forms consisting essentially of:
a) decarbalkoxylated loratadine derivative in a pharmaceutically effective amount;
b) CAPMUL(trademark) MCM C-8;
c) povidone; and
d) Polysorbate(trademark) 80.
There is further disclosed a soft capsule dosage form comprising a fill composition consisting essentially of:
a) loratadine and derivatives thereof in a pharmaceutically effective amount;
b) a mixture of mono- and diglycerides of medium chain fatty acids;
c) povidone;
d) Polysorbate(trademark) 80; and
wherein said soft capsule has a capsule size of 5 minim or less.
Loratadine is the drug name given to the compound known as ethyl 4-(8-chloro-5,6-dihydro-11H-benzo[5,6]cyclohepta[1,2-b]pyridin-11-ylidene)-1-piperidinecarboxylate. A structure for this compound is: 
Loratadine derivatives include compounds having the structural formula of loratadine and having substituents differing from that of loratadine and having substantially the same chemical and therapeutic properties. Loratadine derivatives include, but are not limited to, decarboalkoxylated forms of loratadine, such as 8-chloro-6,11-dihydro-11-(4-piperidylidine)-5H-benzo-[5,6]-cyclohepta-[1,2-b] pyridine, also known as descarboethoxyloratadine (DCL); and azatadine. As used herein and in the claims the phrase xe2x80x9cloratadine and derivatives thereofxe2x80x9d means loratadine or any chemically related antihistamine, including any pharmaceutically acceptable salt thereof. Chemically reacted antihistamines include any halogenated H-benzo-cyclohepta-pyridine.
Loratadine and derivatives thereof can be present in an amount of about 6.3% or less by weight of the total fill composition. Typically, loratadine and derivatives thereof can be present in an amount of about 6.3% to about 3.0% by weight of the total fill composition.
Solvent systems which can be used in accordance with the invention are those which are both moderately lipophilic and have hydrogen bonding capability. Preferably, the solvent system has a hydrophilic lipophilic balance (HLB) value ranging from about 3 to about 7, more preferably ranging from about 4 to about 5. The preferred solvent system of the invention contains a mixture of mono- and diglycerides of medium chain fatty acids. Preferred mixtures of mono- and diglycerides are mixtures of caprylate and caprate. Most preferred as the mixture of mono- and diglyceride medium chain fatty acids is CAPMUL(trademark) MCM-C8 (available from Abitec Corporation, Northampton, England). The mono- and diglyceride mixture can be present in an amount of about 89.0% by weight or less of the total fill composition. When CAPMUL(trademark) MCM-C8 is used, it is preferably present in an amount ranging from about 89.0% to about 70.0%, more preferably about 89.0% to about 80%, by weight of the total fill composition.
The solvent system can further comprise a dispersant composition to enhance uniform dispersibility of the fill in water or gastric juices. The amount of the additional dispersant, however, is present in amount sufficient to enhance uniform dispersion of the fill in water or gastric juices without significantly increasing the volume of the fill. When a dispersant is used, it is preferred that the dispersant be present in an amount of 8.0% by weight of the fill or less. More preferred is a dispersant present in an amount of from about 7.5% to about 5.0%, most preferably from about 7.5% to about 7.0%, by weight of the total fill composition.
A preferred dispersant is a mixture of povidone (polyvinylpyrrolidone) and Polysorbate(trademark) 80 (a polyoxyethylene sorbitan fatty acid esters). Mixtures of povidone and Polysorbate(trademark) 80 can preferably be present in a weight ratio of about 10:1 to about 15:1, respectively.
Compositions according to the invention do not require the presence of additional ingredients such as additives and stabilizers typically associated with soft capsule fill formulations. Without these additional ingredients higher concentrations of loratadine and derivatives thereof can be obtained within smaller fill volumes as compared to existing formulations.
The invention further provides a soft dosage form having a pharmaceutical composition comprising loratadine and derivatives thereof and a solvent system having a mixture of medium chain mono- and diglycerides. In one embodiment, the invention includes a soft capsule comprising a storage stable composition having 10 mg of loratadine in solubilized state in a capsule size as small as 3 minims.
The loratadine compounds of the invention can be prepared according to the method described in Villani U.S. Pat. No. 4,282,233, the entire text of which is incorporated herein by reference. The starting materials and reagents to prepare loratadine and its derivatives are well known in the art and readily available, and loratadine and its derivatives can be synthesized using conventional organic synthesis techniques. Metabolic derivatives of loratadine, such as decarbalkoxylated forms of loratadine, can be prepared by removal of the carbethoxy moiety according to methods known in the art and as described in U.S. Pat. No. 4,659,716, the entire text of which is incorporated herein by reference. For example, loratadine can be refluxed in the presence of sodium hydroxide and ethanol to remove the carbethoxy moiety from the piperidine ring of the compound structure.
Solvent systems which can be used in accordance with the invention are those which are both moderately lipophilic and have hydrogen bonding capability. Preferably, the solvent system has a hydrophilic lipophilic balance (HLB) value ranging from about 3 to about 7, more preferably ranging from about 4 to about 5. Suitable solvent systems include, but are not limited to, polyglycolysed glycerides (such as LABRAFIL(copyright) WL 2609BS available from Gattefossxc3xa9, Binfield, U.K.), propylene glycol monolaurate (such as LAUROGLYCOL(trademark) 90 available from Gattefossxc3xa9), propylene glycol monocaprylate (such as CAPRYOL(trademark) 90 available from Gattefossxc3xa9), and mono- and diglyceride medium chain fatty acids. Most preferred is the mono-, diglyceride medium chain fatty acid mixture CAPMUL(trademark) MCM C8 (commercially available from Abitec Corporation).
The solvent system can further comprise a dispersant composition to enhance uniform dispersibility of the fill in water. The amount of the additional dispersant, however, is present in amount sufficient to enhance uniform dispersion of the fill in water or gastric juices without significantly increasing the volume of the fill. When a dispersant is used, it is preferred that the dispersant be present in an amount of 8.0% by weight of the fill or less. Most preferred is a dispersant present in an amount of from about 7.5% to about 7.0% by weight of the total fill composition.
The dispersant composition used in accordance with the invention can be a combination of povidone together with a surfactant. Suitable surfactants which can be used include, but are not limited to, non-ionic surfactants having an HLB value ranging from about 14 to about 17; polyoxyethylene sorbitan fatty acid esters, such as Polysorbate(trademark) 40, Polysorbate(trademark) 60, Polysorbate(trademark) 20, and Polysorbate(trademark) 120; ethoxylated aliphatic alcohols, such as Oleth-20 (Volpo(trademark) 20 available from Croda, Inc., Parsippany, N.J.), Ceteareth-20 (Volpo(trademark) CS-20 available from Croda, Parsippany, N.J.); and caprylocaproyl macrogol-8 glycerides (LAUROGLYCOL(trademark) 90 available from Gattefossxc3xa9).
A preferred dispersant is a mixture of povidone and Polysorbate(trademark) 80. Mixtures of povidone and Polysorbate(trademark) 80 can be present in a ratio of about 10:1 to about 15:1.0, respectively.
Soft capsules containing pharmaceutical compositions can be prepared using conventional and known encapsulation techniques, such as that described in Stroud et al., U.S. Pat. No. 5,735,105, the entire text of which is incorporated herein by reference. In general, the formulation is deposited between two opposing ribbons of a gel composition. The composition of the ribbons may include gelatin, modified starches, gums, carrageenans and mixtures thereof. Those skilled in the art will appreciate what compositions are suitable. The opposing ribbons are then run between two die rollers having die pockets thereon the surface of which corresponds to the configuration of the desired soft capsule. The composition is sealed within the fused casing.
When formulated in accordance with the invention, a 10 mg loratadine dose can be accommodated by a 5 minim or less size oval soft capsule. A 10 mg loratadine dose can be contained within a capsule size as small as a 3 minim size oval soft capsule. Capsule size volumes of the invention are herein expressed in terms of minims. A minim is a pharmaceutical volumetric unit of measure wherein 1 minim=0.0616 cc.
Soft dosage forms, such as soft gelatin capsules, containing the loratadine compositions of the invention can be orally administered to patients in need of Hi receptor antagonist or antihistamine treatment.
The invention can be further illustrated by the following Examples: